AV0004: Invalid API version number

Cause

An API version specified a negative number.

Rule Description

Specifying an API version as a number removes a class of issues, but the number can still be specified as a negative value.

Consider the following code:

[ApiController]
[ApiVersion(-2.0)]
[Route("[controller]")]
public class ExampleController : ControllerBase
{
    [HttpGet]
    public IActionResult Get() => Ok();
}

The text -2.0 is not a valid API version. This would not detected until runtime.

How to Fix Violations

An API version should always be greater than or equal to 0.1. Update the API version to be well-formed.

[ApiController]
[ApiVersion(2.0)]
[Route("[controller]")]
public class ExampleController : ControllerBase
{
    [HttpGet]
    public IActionResult Get() => Ok();
}

When to Suppress Warnings

It is never safe to suppress this rule because a runtime exception will be thrown when the attribute is initialized.